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International Journal of Chemical Engineering
Volume 2015, Article ID 826709, 10 pages
http://dx.doi.org/10.1155/2015/826709
Research Article

Antioxidant and Antibacterial Assays on Polygonum minus Extracts: Different Extraction Methods

1Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, National University of Malaysia, 43600 Bangi, Selangor, Malaysia
2Department of Agro-Industrial Technology, Faculty of Agriculture, University of Bengkulu, Kandang Limun, Bengkulu 38371, Indonesia
3Institute of Systems Biology, National University of Malaysia, 43600 Bangi, Selangor, Malaysia

Received 11 November 2014; Revised 28 February 2015; Accepted 9 March 2015

Academic Editor: Xijun Hu

Copyright © 2015 Norsyamimi Hassim et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The effect of solvent type and extraction method was investigated to study the antioxidant and antibacterial activity of Polygonum minus. Two extraction methods were used: a solvent extraction using Soxhlet apparatus and supercritical fluid extraction (SFE). The antioxidant capacity was evaluated using the ferric reducing/antioxidant power (FRAP) assay and the free radical-scavenging capacity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The highest polyphenol content was obtained from the medium polarity methanol extract of the leaf portion (645.60 ± 166.68 gallic acid equivalents/100 g (GAEs/100 g)). It also showed the highest antioxidant power for FRAP and DPPH radical inhibition and exhibited the largest inhibition zone in antibacterial activity on Bacillus subtilis (Gram+), Staphylococcus aureus (Gram+), and Escherichia coli (Gram−). The phase behavior and aldehyde profiles were further investigated using SFE with different cosolvents. The results indicated that a 50% ethanol-water cosolvent yielded the best aldehyde profiles in the presence of decanal, undecanal, and dodecanal.